







COPYRIGHT DEPOSIT. 






What 

MAKES UP the WORLD 


UNIFORM WITH THIS VOLUME 


HOW THE WORLD BEGAN 

The Story of the Beginning of Life on Earth 

HOW THE WORLD GREW UP 

The Story of Man 

HOW THE WORLD IS RULED 

The Story of Government 

THE WORLD OF ANIMALS 

The Story of Animals 

THE GARDEN OF THE WORLD 

The Story of Botany 

HOW THE WORLD IS CHANGING 

The Story of Geology 

THE WORLD’S MOODS 

The Story of the Weather 

THIS PHYSICAL WORLD 

The Story of Physics 

OTHER WORLDS THAN THIS 

The Story of Astronomy 


Thomas S. Rockwell Company 
Publishers 
CHICAGO 









II 


Publisher s Note 

This book presents in popular form the 
present state of science. It has been reviewed 
by a specialist in this field of knowledge. An 
excerpt from his review follows: 

“What Ma\es Up the World tells 
something of the story of the trans¬ 
formation of matter—the story of 
chemistry in a very attractive and 
simple way. It should interest and 
stimulate children of ten years of age 
or older” 


Signed: Julius Stieglitz 

Chairman of the Department of 
Chemistry 

The University of Chicago 







The chemist ma\es dyes of many colors out 
of sticky hlac\ coal tar 


































































What 

MAKES UP the WORLD 


‘By 

Elizabeth LeMay Hayes 

o 

Drawings by 
Chester Thomas 


THOMAS S. ROCKWELL COMPANY 

CHICAGO 

1930 


X 


c 



Copyright, 1930, by 

THOMAS S. ROCKWELL COMPANY 

Chicago 


Printed in United States of America 



©CIA 28103 


CONTENTS 


The Puzzle of Fire, Water, Air and Earth ii 
I The Fire Mystery 15 

What is fire? Why does a candle have a 
wic\? Why does fire li\e a draft? Why 
does water put out fire? What becomes of 
the oxygen that goes into the fire? Why 
does a match light when you stride it? Why 
doesn't everything burn? 

II Fire’s Cousins 29 

What is rust? Why do we breathe? How 
does the firefly wor\ his lantern? Why does 
a rotting log glow in the dar\? What be¬ 
comes of the carbon dioxide? 

III Water 37 

What is water made of? Why won't water 
burn? Can fire have water in it? What 
happens when hydrogen meets oxygen? 
What is hard water? 

IV Air 47 

What is air made of? What is nitrogen good 
for? Does nitrogen ever combine? What 
is carbon dioxide good for? How does air 
carry messages to our noses? 

V Earth 59 

What is earth made of? What elements are 
commonest? What does an element loo ^ 
li\e? When is a diamond not a diamond? 
What happens to elements? 


VI Changes 


69 


How do elements get together? What is 
a mixture? What is a compound? What 
causes things to combine? Do things come 
uncombined? 


VII The Story of Chemistry 


81 


How were things found out? Why did the 
alchemists give up? What is an atom? 
What is the mystery of radium? Can the 
alchemist’s dream come true? 


VIII Everyday Chemistry 


9i 


What does chemistry do for the world? How 
does the gasoline ma\e the engine go? What 
is mortar? How does chemistry help the 
plants grow? What is glass? What is rub¬ 
ber? What is a synthetic? What is rayon? 


LIST OF ILLUSTRATIONS 


DYES ARE MADE FROM COAL TAR 4 

THE WATER RUSHES INTO THE JAR 17 

A CANDLE FLAME HAS TWO COLORS 19 

ONE ATOM OF CARBON TAKES TWO OF OXYGEN 23 
OXYGEN AND HYDROGEN BUBBLE UP 38 

WATER APPEARS INSIDE THE JAR 41 

THE CANDLE BURNS FURIOUSLY 49 

A FISH CAN’T BREATHE AIR 51 

WE EAT NITROGEN FROM THE SOIL 53 

FOOD FLIES TO MEET THE NOSE 55 

RADIUM IS USED IN LUMINOUS PAINT 61 

CALCIUM BURNS ON TOUCHING WATER 65 

A CANDLE FLAME MAKES PURE CARBON 67 

THE ATOMS PAY NO ATTENTION TO EACH OTHER 70 
THE ATOMS PLAY RING-AROUND-THE-ROSY 71 

THE ALCHEMISTS LAID THE FOUNDATIONS OF 
CHEMISTRY 85 

CARBON DIOXIDE AND WATER VAPOR DEMAND 
SPACE 96 

MORTAR IS SPREAD BETWEEN BRICKS 98 

GLASS WAS DISCOVERED BY ACCIDENT 103 















THE PUZZLE OF 


FIRE, WATER, AIR AND EARTH 


L ONG ago, before men had decided whether 
the world was round or flat, and before 
they even suspected that it might be traveling 
around the sun instead of the sun around it, 
when the fastest ships were rowed by galley 
slaves and the speediest vehicles were horse- 
drawn chariots, men wondered what the world 
might be made of. 

They had no microscopes then with which to 
examine things; none of the intricate and pre¬ 
cise scientific equipment with which such prob¬ 
lems are investigated nowadays had been 
invented yet. But they observed with their 
eyes and reasoned with their minds. 

They saw earth and air and water. Every¬ 
thing else seemed to grow out of these ancyte- 
turn again into them. Plants grew in the earth, 


11 


12 


using the air and water. Animals ate the plants 
and each other, and men ate both plants and 
animals. Both vegetable and animal matter 
eventually became earth again. 

But they also saw fire, which was not earth 
or air or water. They could not understand 
fire. They decided that it, too, must be a thing 
apart and different. 

The universe, then, they said, must be made 
of fire, earth, air and water. These were 
things, they thought, that could not be taken 
apart into other things. If any one of them 
were lacking, the world and all upon it could 
not exist at all. 

They were almost right, in their way, for 
they could not divide the earth, or air, or fire, or 
water into anything else. But centuries later, 
as the race of men grew wiser, and by long and 
patient effort learned a little more, scientists 
discovered that earth and air and water could 
be taken apart. They found as many as ninety 
different materials went into the making of 
earth, air and water. Every few years another 


13 


such material is discovered. And the end is not 
yet in sight as science progresses. 

But fire, which puzzled men most of all, only 
began to be rightly understood about one hun¬ 
dred and fifty years ago. And the understand¬ 
ing of fire helps to explain many mysteries 
about what the world is made of. 




















Chapter I 


THE FIRE MYSTERY 

T HE reason that fire remained a mystery 
for so long is that men thought it was a 
substance . They thought it was a sort of 
luminous, hot stuff that poured out of things as 
they burned. They came near to being right, 
but they were wrong. 

Fire is not a material substance. It is some¬ 
thing happening. Now just what is it that 
happens when something—say a candle— 
burns? If you watch a burning candle, you 
will see that it slowly becomes shorter—that is, 
the wax is being consumed. You will notice 
also that heat and light are being produced. 
But there are other things going on that you 
cannot see. 

Suppose the candle were set in a shallow bowl 
of water, and a large glass jar were placed over 
is 


What is fire? 


16 WHAT MAKES UP THE WORLD 

it to prevent any fresh air from reaching the 
flame. Now what happens? 

The candle burns just as usual for a moment. 
Then the flame suddenly shrinks, quivers, and 
goes out. Immediately the water rises in the 
jar, and if there was only a little water in the 
bowl there may be a sucking and gurgling noise 
as both water and air are pulled up into the jar! 

Now what has happened here ? Why did the 
candle go out? Why did the water rush up 
into the jar? 

We have already noticed that the flame uses 
up the wax of the candle. It uses up something 
else as well. This something else is a part of 
the air. When the flame had used all of the 
air it could, it went out, and the water came 
in to take up the room in the jar which the 
used air had occupied. 

But the candle didn’t use all of the air in the 
jar. It used less than one-fifth of it. Why 
didn’t it want the rest? For the same reason 
that you don’t eat the apple core. Part of the 
apple is good for eating and part isn’t. Part 



The flame quivers and dies and the water 
suddenly rushes up into the jar 


17 





















WHAT MAKES UP THE WORLD 


Why does a 
candle have 
a wick? 


of the air is good for burning and part is not. 
The part that is not is left in the jar. 

Now the part of the air that is good for burn¬ 
ing is called oxygen. When a candle burns, the 
wax is melted and changed by the heat into a 
vapor, and this vapor and the oxygen rush 
together with such enthusiasm and excitement 
that light and heat are produced. If the oxy¬ 
gen is taken away (as in the jar when the 
oxygen was all used up) the candle goes out. 

If the burning of a candle is vapor from the 
wax combining with oxygen from the air, what 
has the wick to do with it? Why doesn’t the 
wick burn off right down to the wax? Or, if 
the wax is all that is needed for the flame, what 
is the wick put in the candle for? 

If there is any doubt in your mind that the 
wick is needed, just try to light the wrong end 
of the candle, where the wick does not stick 
out of the wax. The heat of the match flame 
will melt the wax, which will begin to drip, but 
it will not take fire. 

The wick is there to help the wax to turn 


THE FIRE MYSTERY 


l 9 


into vapor so that it can combine with the oxy¬ 
gen. It helps the wax up to where the oxygen 
can get at it. 

Now why doesn’t the wick burn right off 
and leave just a little puddle of wax in the top 
of the candle? If you look closely you will 
see that a candle flame is made of two colors. 
The inside of the flame is blue, and the out¬ 
side of it is yellow. 

The hottest part of the flame is this yellow 
outside part, because, being outside, it can get 
the most oxygen. The wick doesn’t burn off 
the candle for the same reason that the flame 
isn’t yellow all the way through. The part 
of the wick inside the flame cannot get enough 
oxygen to burn itself up. 

Watch someone who knows how to build a 
fire well. He will always put paper or wood 
shavings under the wood, and light the paper 
or other light material first. The heat from the 
burning paper will start the wood burning. 
This is because wood must be heated in order 
to form the gas which unites with the oxygen to 



The candle 
flame is blue 
and yellow 


20 


WHAT MAKES UP THE WORLD 


Why does fire 
li\e a draft? 


make the flame. The necessary heat is supplied 
by the burning of the lighter materials—paper 
and shavings. 

For the same reason it is necessary to light the 
wick of the candle so that the heat from the 
burning wick can melt and vaporize the wax. 

A fire in the fireplace won’t burn well unless 
the chimney “draws.” A fire in the furnace 
will not start up brightly unless there is a 
“draft.” A bonfire or a campfire will not be 
a success unless the person who built it knew 
enough to arrange the sticks so that the air will 
come through it freely from underneath. 

Now it stands to reason that if fire is some¬ 
thing combining with oxygen, then the more 
oxygen that is furnished, the more light and 
heat there will be. If the air is very still, only 
the oxygen in the air that is near the fire is 
handy. But if the air is in motion, as it is when 
the chimney draws, or the draft in the furnace 
works well, then there is a large and steady 
supply of oxygen coming to combine with the 
fuel, and the fire burns brightly. 


THE FIRE MYSTERY 


21 


It is true that the candle flame doesn’t need 
much of a draft, but that is because the candle 
flame is only a very tiny fire. The little cloud 
of burning gas which is the flame can very 
easily be blown away from the candle. The 
same wind that blows the flame off the candle 
cools the candle enough so that no more vapor 
is formed, and there is nothing to unite with 
the oxygen, and therefore no flame. This is 
what happens when you blow out a candle. 

The candle went out when shut up in the 
jar because there was no more oxygen left in 
the jar. But why does throwing water on a 
fire put it out as long as there is still plenty of 
oxygen in the air around it? 

The water does two things to the fire. It 
shuts away the oxygen from the fuel so that, 
like the candle in the glass jar, the fire lacks the 
oxygen to keep on burning. But water also 
cools the fuel, so that, like the candle when 
you blow it out, it is no longer hot enough to 
go on making gas to unite with the oxygen 
to form the flame. 


Why does water 
put out fire? 


22 


WHAT MAKES UP THE WORLD 


What becomes 
of the oxygen that 
goes into the fire? 


There are other ways of putting out fire than 
by pouring on water. A good way to put out 
a fire out-of-doors is to shovel sand or dirt on 
it. The sand or dirt shuts the fuel away from 
the air, and puts out the fire by depriving it of 
oxygen and starving it to death. 

In the same way a fire may be stifled by throw¬ 
ing a piece of rug, or a coat over it. Even 
things that burn easily by themselves will put 
out fire by shutting the air away from it. 

Now the candle in the jar used up quite a bit 
of oxygen, as the water rising in the jar proved. 
What became of it? Once upon a time it 
might have been supposed that the fuel was 
actually destroyed in the burning, but now we 
know that nothing is ever really destroyed. It 
is merely transformed into something else. 

Most of the things we burn are made of a 
material called carbon . The white wax of the 
candle is mostly carbon. Coal is almost pure 
carbon. Wood is largely carbon. Carbon is 
generally a solid stuff, but it is also found 
in many vapors or gases. That is what 


THE FIRE MYSTERY 


23 


happens when the candle burns. The wax 
vapor that combines with the oxygen to make 
the candle flame contains carbon. 

When the carbon and oxygen combine, they 
form a gas that you can neither see nor smell. 



One atom of carbon always ta\es two atoms of 
oxygen to form a molecule of carbon dioxide 


Its name is carbon dioxide, which means that 
each carbon atom has two hands, and takes an 
atom of oxygen by each hand. This little ring- 
around-the-rosy formation is neither carbon nor 
oxygen, but a molecule of the gas carbon 
dioxide. 


24 


WHAT MAKES UP THE WORLD 


One of the curious things about this new gas, 
carbon dioxide, is that it is very willing to dis¬ 
solve in water, just as salt or sugar will. The 
carbon dioxide which was formed as the candle 
burned in the jar went into the water, and the 
water rose to take the place of the oxygen which 
had been in the jar. 

There is always some carbon dioxide in the 
air. In large quantities in a shut-up room it 
makes people feel drowsy or even gives them 
headaches. But there is very little danger of 
its occurring in a quantity capable of doing 
much harm to you. 

Sometimes, however, when a stove or a char¬ 
coal burner is burned in a closely shut-up room, 
the oxygen grows scarce and the carbon atom 
can find only one atom of oxygen to join hands 
with. The result is carbon mon-oxide, which 
is a deadly poison gas, and very dangerous be¬ 
cause it can neither be seen nor smelled. 

It is very important that a room with a fire 
in it should be well ventilated, and that an auto¬ 
mobile engine (which burns gasoline, which is 


THE FIRE MYSTERY 


25 


largely carbon) should never be started in a 
garage with closed doors, lest this poisonous gas 
should be given a chance to do harm. 

If a match would light only when exposed to 
a flame, there would be nothing extraordinary 
about it. But neither would it be useful. 
There are many things which will take fire 
when held to a flame; but a match ignites when 
it is scratched on something rough. 

Rub your finger rapidly for several seconds 
on something slightly rough, such as a piece 
of woolen cloth. Soon the end of your fingers 
will feel noticeably warm. You have produced 
heat by friction. 

The head of a match is made of a mixture 
in which there is a material called phosphorus. 
Pure phosphorus is so eager to combine with 
oxygen that it must be kept under water to keep 
it from bursting into flames. 

The phosphorus used in the match head is 
combined and mixed with other substances so 
that it will not ignite until someone wants it to. 
When a match head is drawn rapidly over the 


Why does a 
match light 
when you 
stride it? 


26 


WHAT MAKES UP THE WORLD 


Why doesn't 
everything burn? 


sandpaper on the box, the friction produces a 
small amount of heat. This heat is sufficient 
to cause the phosphorus of the match head to 
begin combining with oxygen. The flare of 
the match head is enough to cause the wood of 
the match stick to begin to burn. 

Before people learned about phosphorus and 
how to use its eagerness for oxygen in lighting 
their fires, lighting a fire was a very difficult 
and tiresome and disagreeable task. 

Phosphorus is not the only substance that is 
very fond of oxygen. Dynamite and T.N.T., 
as well as fire crackers and Fourth of July fire¬ 
works, all contain substances so eager for oxygen 
that they will seize it suddenly and in large 
quantities at the first opportunity that offers. 
And that is how an explosion is made. 

Why doesn’t everyone like spinach? There 
are, fortunately, a number of things that don’t 
care for oxygen and won’t go half way to meet 
it. And oxygen doesn’t care for them. 

Then, too, there are many things that don’t 
want any oxygen because they already have all 


THE FIRE MYSTERY 


27 


that they can carry. That is the reason the 
carbon dioxide will not burn. 

There is a material called asbestos, for in¬ 
stance, which is really a kind of stone. But it 
doesn’t look like stone, for it can be made into 
cloth. The important thing about asbestos is 
that it absolutely will not burn, any more than 
stones will burn in a bonfire. 

Because asbestos will not burn it is made into 
many useful things. Firemen wear gloves 
made of it, so that they need not burn their 
hands as they work to put out fires. 

Of course, asbestos is only one of these non¬ 
burning substances. More and more of them 
are being used, nowadays, to make our homes 
and cities safe from the peril of fire. 

But there are also many things which will 
burn, and which we use every day, without 
ever seeing them catch fire. 

Just as some things, a match head, for in¬ 
stance, catch fire much more easily than others, 
so there are many things which can be burned, 
but only with great difficulty. 


28 


WHAT MAKES UP THE WORLD 


All metals can be burned. Yet our homes 
are heated with iron furnaces, and our food is 
cooked on the stove in aluminum saucepans 
and iron frying pans. Yet you never see these 
metals on fire. 

A great amount of heat and a great quantity 
of oxygen are necessary for the burning of such 
substances as these metals. The fire which 
burns so furiously in the furnace on a cold day 
is not hot enough to melt the iron of the fur¬ 
nace, to say nothing of burning it. Therefore, 
so far as our everyday needs are concerned, the 
common metals which we use are safely con¬ 
sidered to be fireproof. 


Chapter II 


FIRE’S COUSINS 

E VERYONE has frequently seen the red or 
brownish scales of rust on iron or steel that 
has been left where air, particularly moist air, 
could get at it. Rust is so common a thing that 
we forget to wonder about it. 

But common as it is, it is rather wonderful. 
For when we see a rusty nail, for instance, we 
are seeing the same thing that we see when we 
look at a bonfire. 

In a fire, a part of the fuel is combining with 
oxygen to form carbon dioxide. In the nail, 
the iron itself is combining with oxygen to form 
iron oxide, which is usually called rust. But 
these two processes are not at all alike to watch. 

The difference is that in the bonfire the com¬ 
bination is taking place so rapidly that light and 
heat are formed, and the effect is quite splendid 


What is rust? 


29 


30 


WHAT MAKES UP THE WORLD 


Why do we 
breathe? 


to look at, and pleasant to feel from a little dis¬ 
tance. But the rusty nail is carrying on the 
same process so slowly that there is no light, 
and no heat that anyone can feel. The iron 
is taking hundreds of times as long to do the 
very same thing. 

One of the reasons we know that rusting iron 
is really taking oxygen out of the air and com¬ 
bining with it to form the rust, is that a piece 
of iron, allowed to rust all the way through, 
weighs quite a little more than the same piece 
of iron before the rusting process started. This 
is true because the weight of the rust equals the 
weight of the original iron, plus the weight of 
all the oxygen which it has taken from the air 
in becoming rust. 

If the question, “why do we breathe?” were 
answered “so that we may rust,” it would seem 
very silly indeed. Perhaps the answer “so that 
we may burn” would seem a little less ridic¬ 
ulous and be a little nearer the truth. 

What happens when we breathe? We pull 
some air down into our lungs. In the depths of 


FIRE’S COUSINS 


3i 


our lungs the oxygen from the air is absorbed 
by the blood. The blood carries the oxygen 
supply to where it is needed to burn waste prod¬ 
ucts, and to convert the food which we have 
eaten into energy. The oxygen and the food 
combine in our blood in a sort of a slow fire, 
which does not produce light, but which does 
produce heat and energy, or power. 

The air in our lungs, from which the oxygen 
has been taken, and to which some carbon 
dioxide has been given back, is pushed out of 
the lungs by the action of the breathing muscles, 
and we are ready to take another breath and 
do it over again. 

Now when something has been combined 
with oxygen, we say that it has been oxidized. 
When a candle burns, the carbon in it is oxi¬ 
dized to form carbon dioxide. When iron rusts, 
it is oxidized, and the result is iron oxide. When 
we breathe, certain carbon materials (for most 
of the food we eat is mainly carbon) are oxi¬ 
dized to form carbon dioxide, which is carried 
out with our outgoing breath. The heat and 


3 2 


WHAT MAKES UP THE WORLD 


How does the 
firefly wor\ 
his lantern? 


energy formed by the oxidizing process remain 
behind in our bodies to warm them and furnish 
the power for moving and living. The warmth 
of our bodies is proof that we are, in a sense, 
furnaces in which a kind of fire is burning. 

The firefly, and certain other insects and 
simpler forms of life, know a trick or two that 
man hasn’t quite figured out yet. Possibly 
when we do find out how to make light in the 
firefly’s way it may revolutionize our methods 
of lighting our cities and houses. 

The remarkable thing about the firefly’s 
lighting arrangements is that they produce the 
most economical form of light known. It is a 
light without heat. Every way man has of 
making light creates heat too, and wastes a lot 
of energy doing so. Hold your hand near an 
electric light bulb that has been burning for a 
few minutes and you will feel the heat that is 
going to waste. 

But although we have not yet learned how 
the firefly does it, this much we know—the 
process requires oxygen, just as burning does. 


FIRE’S COUSINS 


33 


The oxygen, which the firefly takes out of the 
air, is carried in the blood to where it is needed, 
just as ours is. But the firefly needs the oxygen 
for one more purpose than we do—he uses it to 
light his lantern. 

If you have ever walked through the woods 
at night, and suddenly come upon a mass of 
pale, greenish light in the darkness, you may 
have thought, just for a moment, that you 
were seeing a ghost. 

If you investigated your “ghost,” however, 
you probably found it was a rotting log. But 
for a rotting log to glow by itself in the dark is 
sufficiently uncanny. 

In the first place, the log is decaying. This 
process is very much the same thing as the rust¬ 
ing of a piece of iron, with this exception: while 
the rusting of iron is a simple process involving 
only the iron and the oxygen of the air, the 
decaying of animal or vegetable matter is much 
more complex because so many more materials 
are involved in the process. 

Whereas iron is made of just one thing—iron 


Why does a 
rotting log glow 
in the darf{? 


34 


WHAT MAKES UP THE WORLD 


What becomes 
of the carbon 
dioxide? 


—animal or vegetable matter is made of very 
complex arrangements of a number of things. 
Furthermore, while iron and oxygen carry on 
the process of oxidation all by themselves, there 
are a number of fungi and bacteria willing and 
eager to help animal or vegetable matter decay. 

That is what is happening in the case of the 
glowing log. In the first place, it is oxidizing. 
In the second place, a fungus has settled down 
to help the work of decay along. And in the 
third place, this fungus, for unknown reasons 
of its own, is manufacturing a material which 
is also oxidizing. It is this stuff manufactured 
by the fungus which is burning with a very 
slow fire. This slow fire produces carbon 
dioxide just as the candle does, but much more 
slowly. It doesn’t produce any noticeable heat, 
but it does give off enough light to startle one 
in the woods on a dark night. 

When you watch the solid wax of the candle 
disappearing into the flame, or a great log in the 
fire dwindling away to a few ashes, it may be 
hard to believe that nothing is being destroyed 


FIRE’S COUSINS 


35 


and lost. It is because the carbon dioxide (as 
well as some other oxides) into which the solid 
matter of the candle or log is being transformed 
is invisible. A thing is no less real for being 
invisible. Take air, for example. It is very 
real, as anyone would soon find out if he tried 
to get along without it. 

We might think that with all the fires in the 
world producing carbon dioxide, and all the 
animals in the world, men included, giving it 
off with every breath, in the course of time the 
world would be full of carbon dioxide and there 
would be no free oxygen left. 

And indeed, this could happen, in the course 
of time, were it not for one very important 
thing in nature’s scheme of economy. Plants 
differ from animals in a number of very striking 
respects. One of them is the way in which 
they can manufacture their own food. 

Plants take in carbon dioxide from the air, 
and, with energy which is filtered out of sun¬ 
shine by their green coloring matter, they 
separate the oxygen from the carbon. They 


36 WHAT MAKES UP THE WORLD 

give back the pure oxygen to the air, and use 
the carbon to build up their own tissues. 

Since animals cannot perform this trick, they 
have to get their food by eating the plant, which 
made it from the carbon dioxide, or by eating 
another animal, which ate the plant which “ate” 
the carbon dioxide. 

All living things, both vegetable and animal, 
are made largely of carbon. When we eat 
lettuce, or spinach, or any vegetable or cereal, 
we are eating carbon which the plant itself 
extracted from the carbon dioxide of the air. 
But when we eat beefsteak, we are eating carbon 
which the steer took in in the form of grass, and 
which the grass took out of the air. 

So we may imagine these things—carbon and 
oxygen, and many other materials as well, 
changing about from one combination to an¬ 
other, but never destroyed. 


Chapter III 


WATER 

L ONG ago, wise men would have laughed 
at this question and replied that water was 
—water. It could be frozen into ice; it could 
be vaporized into steam, but whether solid, 
liquid or gas it was still water. But of course, 
they did not have electric currents at their dis¬ 
posal, with which to take water apart and so 
find out what it is made of. 

But modern scientists can do this. An elec¬ 
tric current is made to pass through the water. 
As it does so, a gas is seen to bubble up from 
the point where the electricity enters the water, 
and another gas from the point where the 
electricity leaves the water. One of these gases 
is oxygen: the very same stuff that is necessary 
for fire, for breathing, for rusting—all oxidation 
processes, as you know. 

37 


What is water 
made of? 


38 


WHAT MAKES UP THE WORLD 


The other gas, of which there bubbles up 
just twice as much as of oxygen, is called hydro¬ 
gen. Hydrogen is a very light gas, much lighter 
than air, which is used in balloons and 
airships and other lighter-than-air craft. It 



When an electric current is passed through water , 
oxygen and hydrogen come up in bubbles 


has one great disadvantage for this purpose. 
Although it is the lightest gas known, and 
therefore has the most lifting power, it is very 
willing to unite with oxygen, and burn, or 
explode. Many fatal accidents have happened 
to hydrogen-filled airships because of hydro¬ 
gen’s fondness for oxygen. 

If the water is weighed before it is separated 
into these two gases by the electricity, and the 













WATER 


39 


gases are carefully captured and weighed, it is 
found that the gases, together, weigh exactly as 
much as the amount of water which has dis¬ 
appeared in the process. 

We know that fire is only oxygen and some 
other substance combining with such rapidity 
and enthusiasm that light and heat are created. 

And hydrogen is one of the best fuel gases 
known. Now if water is made of these two 
gases, why carit we burn water? 

Why didn’t the candle burn the carbon 
dioxide in the glass jar when the oxygen was 
gone? You will recall that in making carbon 
dioxide, each carbon atom took two atoms of 
oxygen by the hand, so to speak. The oxygen, 
held by the carbon, was no longer free to join 
with more carbon, and therefore there could be 
no more burning. 

In the case of water, each atom of oxygen has 
joined itself to two atoms of hydrogen. Now 
there are very few things in the world that are 
as devoted to each other as these oxygen and 
hydrogen atoms. Consequently, being so well 


Why won't 
water burn? 


40 


WHAT MAKES UP THE WORLD 


Can fire have 
water in it? 


satisfied with each other, neither the oxygen nor 
the hydrogen is willing to let go of the other in 
order to combine with something else. Since 
burning is the combination of oxygen and an¬ 
other substance, water will not burn. 

Sometimes, however, something does happen 
to cause the oxygen and hydrogen to let go of 
each other. If a few drops of water are 
sprinkled on a very hot fire, the exceedingly hot 
carbon in the fire may be so greedy for oxygen 
that it will actually snatch the oxygen away 
from the hydrogen. In that case, the hydrogen 
will immediately burn up too. 

But that cannot be called water burning, for 
the water must cease to be water and become the 
two gases before the burning happens. 

Carbon dioxide is carbon and oxygen in com¬ 
bination. Water is hydrogen and oxygen in 
combination; and if we want a longer name for 
it we can call it hydrogen oxide. 

When the candle was burned under the jar, 
something else happened which wasn’t men¬ 
tioned before because there was enough to talk 



When a candle is burned under a jar, water 
condenses on the inside of the glass 


41 






















































































42 


WHAT MAKES UP THE WORLD 


about without it. As the candle burned under 
the jar, the glass clouded up, because a deposit 
of water vapor formed on the inside of the jar. 

We can get the same effect by holding a cool 
glass over the spout of the tea kettle when there 
is steam coming out, or we can find it on the 
window panes when the air inside is warm and 
moist, and that outside is cold. It is just water 
which the air carries until it finds something 
cool to put it down on. 

But where did the air in the glass jar pick up 
this water? We might suppose it came from 
the bowl of water in which the candle was sit¬ 
ting. But if there is no bowl of water at all the 
water vapor will gather on the glass while the 
candle burns inside. 

We must remember that, while the wax of 
the candle is largely carbon, it is not all carbon. 
There are various other things in the wax, and 
one of them is hydrogen. When the candle 
burns, the carbon oxidizes to form carbon diox¬ 
ide and the hydrogen oxidizes to form hydro¬ 
gen oxide, which, of course, is water. The 


WATER 


43 


water is formed as a vapor in the air, and the 
air deposits it on the cooler glass. 

Suppose a jar of oxygen and a jarful of 
hydrogen were mixed together. What would 
happen? Would we have a jarful of water, just 
a jarful of mixed gases, or an explosion? 

If the hydrogen and oxygen were just quietly 
put together, nothing would happen at all. 
There would be a jarful of mixed gases. Since 
both of these gases look like air, the mixture 
would look like air, but it would not be air. 

But if anyone were careless enough to let this 
mixture of gases come into contact with a flame, 
or even the tiniest spark, something would 
happen immediately. There would be a tre¬ 
mendous explosion. 

But suppose the hydrogen and oxygen were 
introduced to each other in a different way. 
Suppose the hydrogen were allowed to come out 
through a small jet, like a gas jet, and burn in 
the air, thereby taking the oxygen out of the 
air as it wanted it. 

The result would be a small, colorless flame 


What happens 
when hydrogen 
meets oxygen? 


44 


WHAT MAKES UP THE WORLD 


What is 
hard water? 


producing a great deal of heat. If a glass bell 
were arranged above this hydrogen flame, water 
would be seen condensing upon the glass, and 
finally rolling down in drops. Burning hydro¬ 
gen produces hydrogen oxide, and nothing else. 
When hydrogen is burned, it might be said that 
the smoke and ashes are water. 

Of course we might say that water is hard 
when it is frozen solid. But that is not what is 
generally meant when we speak of water 
which is “hard.” 

The water which is produced by the hydro¬ 
gen flame is pure water—that is, it contains 
nothing but hydrogen and oxygen. But the 
water we daily drink and wash in is not manu¬ 
factured by a hydrogen flame. It comes from 
springs, wells and lakes. It seeps through rock 
and sand before it is finally brought to us by 
pipes to flow out through our faucets. 

While it is pure enough so that it is good for 
drinking, it has other things in it besides hy¬ 
drogen and oxygen. 

When rain falls, it absorbs some carbon 


WATER 


45 


dioxide out of the air. As the rain water seeps 
through limestone under the ground, this car¬ 
bon dioxide helps the water to dissolve some 
lime. Other mineral matter is dissolved while 
the water is underground. 

All these things help the water to taste good, 
if there is not too much of them. The chances 
are that we should find the pure water produced 
by the hydrogen flame a little flat to taste be¬ 
cause of its very purity. 

But if water has a little too much of this 
stony material, it makes itself disagreeable in a 
number of ways. For instance, the tea kettle 
in which such water is heated acquires a thick 
coating of greyish yellow stony stuff on the 
bottom and sides. This happens because the 
carbon dioxide was holding the lime dissolved 
in the water. When the water was boiled, a 
good deal of the carbon dioxide bubbled away, 
and a corresponding amount of lime was 
dropped on the bottom of the kettle. 

But the most inconvenient thing about the 
“hard” water is the way in which soap behaves 


46 WHAT MAKES UP THE WORLD 

in it. If wc take two bowls, one of a soft water 
such as rain water, and one of a hard water 
containing a good deal of lime, and with a good 
cake of soap wash our hands first in one bowl 
and then in the other, we observe a great differ¬ 
ence between the two kinds of water. 

In the soft water the soap will lather up 
freely. In the hard water it will hardly lather 
at all. We notice little white curds of soap 
floating in the hard water, but they will not 
make soap suds. Why is this? 

The soap, in hard water, combines with the 
mineral matter to form these curds. If we put 
enough soap in the hard water we can get 
almost as good a lather as with the soft water; 
but this strong mixture of soap and mineral¬ 
laden water is very harsh on the skin. 

In the soft water, the soap is offered nothing 
to combine with except the dirt on your hands, 
which it does quickly and efficiently. 


Chapter IV 


AIR 

W E ALREADY know that air has oxygen 
in it. We also know that it has more in 
it than oxygen. When the candle burned in 
the jar, less than one-fifth of the air in the jar 
was used up in the burning. If the candle had 
been able to use every last trace of oxygen, and 
the carbon dioxide formed could have been 
taken out of the jar without disturbing anything 
else, about four-fifths of the amount of the origi¬ 
nal air would have been left in the jar. 

We know one thing about this gas remaining 
in the jar after the oxygen has been removed 
from the air. We know that the candle will not 
burn in it. In other words, this gas will not 
support combustion . 

If we were to put a live mouse into the jar, he 
would make no better of the situation than did 


What is air 
made of? 


47 


WHAT MAKES UP THE WORLD 


What is nitrogen 
good for? 


the candle. A gas which will not support 
combustion will not support life, for, as you 
know, both are oxidation processes. 

This gas, which is called nitrogen, is not 
nearly so eager to combine with things as is 
oxygen. In the atmosphere it is what we call 
an inert gas, which means that it is inactive. 

Air is approximately one-fifth oxygen and 
four-fifths nitrogen. Scientists, with their fine 
instruments, can find small quantities of other 
things in the air. There is always water in the 
air in the form of vapor. There is always a 
little carbon dioxide, and some hydrogen. 
There are traces of other gases which we do not 
know so well, such as argon, and a very small 
amount of helium. 

Really to appreciate what a good thing this 
inert gas called nitrogen is, we shall consider 
what it would be to get along without it. Since 
it is impractical to try such an experiment on 
ourselves, we might try it on something else. 

You recall the behavior of the candle in the 
jar of air. Suppose we had a jar of oxygen 


AIR 


49 


under which to place our lighted candle. It 
would behave very differently. 

The candle flame would be much larger than 
usual, and much hotter. The wax, exposed to 
this torch-like flame, would melt much more 
rapidly, and the candle would shrink before our 
eyes. But as soon as the oxygen in the jar were 




In an atmosphere of pure oxygen, combustion 
goes on at a terrific rate 

all converted into carbon dioxide, the candle 
flame would die down, flicker and go out, just 
as it did in the jar of ordinary air. 

If we put a mouse into a similar jar of oxygen, 
it would behave much as the candle did. That 


















50 


WHAT MAKES UP THE WORLD 


Does nitrogen 
ever combine? 


is, it would be several times as active as a mouse 
under normal conditions. The little creature 
would be possessed by a furious fever of activity. 

If the mouse were left in the jar, and the jar 
were large enough to hold enough oxygen, the 
mouse would soon be worn out, just as the 
candle would soon be burnt up. The mouse 
was not made to live in an atmosphere of pure 
oxygen. Its little mechanism would soon wear 
out under such hard usage. 

It is obvious, then, that none of us would live 
very long or very happily in an atmosphere of 
pure oxygen. But oxygen diluted with four 
parts of quiet, inert nitrogen, gives us just what 
we need. We have enough oxygen to supply 
ourselves with warmth and energy, but not 
enough to wear out our machinery doing so. 

But nitrogen is not always inert. It will com¬ 
bine with other elements. We wouldn’t be 
alive if it didn’t. Nitrogen, along with carbon, 
hydrogen and oxygen, is absolutely necessary to 
life for both plants and animals. 

We might think it would be no problem at all 


AIR 


5i 


for plants and animals to find all the nitrogen 
they need, since they get enough oxygen with¬ 
out difficulty, and there is four times as much 
nitrogen as oxygen in the air around us. 

But the truth is that we can no more get any 
of this nitrogen out of the air by breathing it 



A fish out of water cannot get oxygen 
out of the air 


than a fish out of water can get oxygen out of 
the air. And even though plants can separate 
carbon out of carbon dioxide, they cannot take 
free nitrogen out of the air. 

But fortunately, there are many compounds 
of nitrogen in the soil. Good soil, such as plants 



52 


WHAT MAKES UP THE WORLD 


What is carbon 
dioxide good for? 


grow well in, is full of this valuable material. 

The plants take nitrogen out of the soil. Most 
of it they store up in their seeds. This nitrogen 
in the seeds is combined with a number of other 
materials into a substance which we call protein. 

Protein is one of the types of food necessary 
to the health of animals and men, because it is 
from this source that they receive the nitrogen 
which the plants took out of the soil. 

We get our proteins from the seeds of plants— 
such as cereals, beans and nuts—from the flesh 
of animals which have eaten proteins and stored 
them up in their own bodies, and from eggs. 

Carbon dioxide is a very good thing from the 
point of view of a plant, for the plant uses it to 
manufacture its foodstuff. Without green 
plants, there would be no life on the earth, for 
there could be nothing at all to eat. And with¬ 
out carbon dioxide the green plants couldn’t 
carry on this important work. 

Therefore, carbon dioxide is a very good 
thing, from everyone’s point of view. But like 
many other things, carbon dioxide has its place. 



The nitrogen compounds in the soil find their 
way into our bodies 


53 











































































54 


WHAT MAKES UP THE WORLD 


One of its places, strangely enough, is in ice 
cream soda. The “fizz” in soda water and pop 
is simply carbon dioxide in solution. It gives 
the tang to ginger ale and root beer, and almost 
all of our familiar soft drinks. 

Another queer place where carbon dioxide is 
a great help is in cake, biscuits, cookies, and 
other baked stuff. The cook puts in baking 
powder or soda to make these things light, but 
it is carbon dioxide which does the work. The 
soda which is used in baking (and which is also 
the chief part of the baking powder) is bicar¬ 
bonate of soda, which name tells us that it con¬ 
tains a good deal of carbon and oxygen. 

When the carbon and oxygen are combined 
with the moisture in the dough, and subjected 
to heat in the baking process, much carbon 
dioxide is given off. This carbon dioxide tries 
to escape in little bubbles, which become impris¬ 
oned in the dough, and make the air spaces 
which give the cake or biscuits their light and 
airy texture. 

How is it that when we come into the house 



When you smell dinner cooking it is because some 
of the food has flown through the air to meet you 


55 



























































How does air 
carry messages 
to our noses? 


56 WHAT MAKES UP THE WORLD 

just before dinner time, there is frequently some¬ 
thing waiting for us just inside the door to tell 
us what we are about to have to eat? 

This something is a smell or odor, and it 
speaks loudly of baked beans, or steak and 
onions, or apple pie, or gingerbread. We 
receive this message up inside our heads in a 
little chamber to which the nose is the corridor. 

There it is received by some efficient reporters 
called the olfactory nerves which immediately 
flash the news to the brain, which is just behind 
them. That is how we come to know of it. 

But the question is, how did the message 
come from the beefsteak in the pan to your nose 
near the front door? 

Remember what happens to the candle wax 
when it is heated by the flame of the wick? It 
vaporizes—changes to a gas which contains 
some of the solid matter in the candle. When 
a beefsteak, or a pot of beans, or an apple pie, or 
almost any foodstuff is heated, some of it be¬ 
comes vapor and mixes with the air. 

Now flavors vaporize very easily. A large 


AIR 


57 


part of the sense of taste is really the sense of 
smell. As we eat, some of the vapor from the 
food we place in our mouths sneaks off up a 
back stairway, and gets to the olfactory nerves: 
so what we taste, we really smell too. 

Since the taste part of foods vaporizes easily, 
naturally some of it vaporizes while the food is 
cooking. Along with a good deal of water, in 
the form of steam, and some carbon dioxide and 
other fumes if the food is allowed to burn, these 
smells go wandering off into the atmosphere. 

Air is quite a lively substance, as we can 
readily believe by remaining in a room with an 
uncorked bottle of ammonia. Smells, especially 
strong smells, travel quite rapidly. 

When we come in the front door and find a 
smell of gingerbread or doughnuts waiting just 
inside it, we know this: that a very small 
quantity of gingerbread or doughnut has actu¬ 
ally got up out of the pan, and, in the form of 
vapor, has flown out to meet us. 

The things which you smell the most are 
those which vaporize the most easily. Per- 


5» 


WHAT MAKES UP THE WORLD 


fumes are substances which vaporize easily and 
which affect the olfactory nerves favorably. 
The scent of flowers comes from a tiny drop 
of nectar deep in the flower. 

Some things have only a faint smell, such 
as unfinished wood. A clever lumberman can 
distinguish many kinds of wood by the scent 
of the freshly cut timber. But unless there 
were a great deal of it around you might not 
even notice that there was a scent to the wood. 

Of course there are many things which have 
no odor at all, because no vaporization is going 
on sufficient to carry the message to your nose. 


Chapter V 


EARTH 

T HE ancients named fire, water and air 
“elements.” But as we understand them 
now, fire is something happening; water is 
made of hydrogen and oxygen; and air is a 
mixture of oxygen and nitrogen. The fourth 
“element” of the ancients was earth. What do 
we find earth is made of? 

We have discussed several materials: oxygen, 
nitrogen, hydrogen, carbon, and iron. Phos¬ 
phorus, argon and helium have been named. 
These are only eight of the materials which 
modern scientists call the dements . There are 
at least eighty others. 

What is an element? It is something which 
isn’t made of anything else. There are many 
other things which contain more than one ele¬ 
ment. But an element alone, in its pure state, 


What is earth 
made of? 


59 


6o 


WHAT MAKES UP THE WORLD 


doesn’t contain anything but itself. Thus, iron 
is an element. But rust cannot be an element, 
because it contains both iron and oxygen, and is 
therefore a compound. 

There are many elements whose names will 
sound very familiar, and there are many others 
which are not so commonly known. Alum¬ 
inum, copper, iron, gold, silver, lead, nickel, 
platinum, tin, zinc—all these are familiar 
because they are materials out of which are 
made many common objects which we see about 
us every day. 

Iodine is familiar as a first-aid precaution for 
cuts and scratches, although the red liquid used 
for this purpose is not pure iodine. Helium is 
becoming a well known word through the use 
of this gas in lighter-than-air craft. We are 
acquainted with mercury as the silver liquid in 
thermometers. Phosphorus, as we know, is 
what makes matches light. Nearly everyone 
has heard of radium as something very valuable 
in the healing of disease, and we have seen it in 
exceedingly minute quantities on luminous 


EARTH 


61 


watch dials and other things made to be seen 
in the dark. 

To these we can now add as familiar ac¬ 
quaintances, carbon and the gases: oxygen, 
nitrogen and hydrogen. 

But among the list of elements there are not 
a few which have astonished jawbreakers for 
names, and which we hardly ever hear of: moly¬ 
bdenum, praseodymium, ytterbium and zircon¬ 
ium, for instance. There are many of these 
long names in the list of elements, but we need 
not be bothered with them. They are unim¬ 
portant to us because they occur in small 
quantities, and they are not commonly used by 
men, nor are they, so far as anyone knows, at all 
necessary to our welfare. 

The commonest element of all is that very 
important one—oxygen. It composes about 
half of the earth’s crust. Most of it is not in 
its free form, of course, but largely in combi¬ 
nations with other things. 

For example, plain sand is made up of grains 
of quartz . Quartz is the oxide of an element 



Radium is used in 
luminous paint 


What elements 
are commonest? 


62 


WHAT MAKES UP THE WORLD 


called silicon . Limestone contains oxygen, car¬ 
bon, and an element called calcium. Both sand 
and limestone are very common things, and so 
an amazing amount of the world’s supply of 
oxygen is imprisoned in them. 

We already know that one-fifth of the 
atmosphere is oxygen. Water consists of two 
atoms of hydrogen to one atom of oxygen. But, 
inasmuch as an oxygen atom is just sixteen 
times as heavy as a hydrogen atom, eight-ninths 
of the weight of water is oxygen. 

The next commonest thing is silicon, which 
probably constitutes a quarter of the crust of the 
earth. A great deal of silicon occurs in com¬ 
bination with oxygen in the form of sand. 

Calcium (which is partner to oxygen and 
carbon in limestone), aluminum, iron, with 
three which are probably strange to you: mag¬ 
nesium, potassium, and sodium, are all very 
important in the composition of the earth. 

We have been speaking of the earth’s crust 
as if its center didn’t matter at all. As a matter 
of fact, it doesn’t matter much to us. The inside 


EARTH 


63 


of the earth, except for a few thousand feet 
down, is inaccessible to us, and therefore 
unimportant. The inner parts of the earth are 
probably composed of the same substances as 
its outer parts. 

The plants and animals which live upon the 
earth are made, mostly, out of carbon, oxygen, 
hydrogen, and nitrogen. Calcium (the same 
element that is in limestone), phosphorus 
(which lights the match), sulphur, potassium, 
iron and other substances are necessary for life. 

It is hard to believe that our bodies are largely 
made of the same stuff as air and water, but it 
can be thought of in this way: The human 
body is about 65 per cent water. That accounts 
for quite a lot of oxygen and hydrogen. We 
eat a great deal of food which contains nitrogen, 
and a part of that nitrogen is stored up in the 
tissues in the form of protein, just as it was 
stored in the tissues of the steer from which the 
beefsteak came. But the bulk of our food is 
carbon. Naturally our bodies are built of the 
things we eat. There is nothing else they could 


6 4 


WHAT MAKES UP THE WORLD 


What does an 
element loo\ li\c? 


be made of, so is it any wonder that we con¬ 
tain a lot of carbon? 

Some elements we know the appearance of 
very well. Gold, iron, copper, silver and others 
we see very often. We know, too, that there 
are elements that we do not see at all under 
normal conditions. The gases: oxygen, hydro¬ 
gen, nitrogen and many less familiar ones, such 
as argon, look like nothing but empty space. 

There are elements that no one would ever 
have seen in their pure state, had it not been for 
the scientists called chemists, who have sep¬ 
arated them from the combinations in which 
they are always found. 

Phosphorus and calcium, which are necessary 
in our bones and teeth, are two of these sub¬ 
stances which existed nowhere in the world, 
except in combinations with other things, until 
chemists took the combinations apart. Pure 
phosphorus looks like white wax; but unless it 
is kept under water where no free oxygen can 
get at it, it immediately begins to rust into red 
phosphorus, or it catches lire and burns. 


EARTH 


65 


Calcium is really a metal, which resembles 
bright, white tin, but is soft enough to mould 
with the fingers. It would be very dangerous 
to mould it with the fingers, however, for the 



The metal calcium bursts into flame when 
dropped in hot water 


warmth and moisture of the hand is sufficient 
to set it on fire. Calcium is so eager to unite 
with oxygen that it will even take oxygen out 
of its combination with hydrogen. That is, 
calcium will burst into flames upon touching 
hot water! No wonder that all the calcium in 
the world was in combinations until chemists 
learned how to separate it out! In order to keep 
pure calcium from getting hold of oxygen and 









66 


WHAT MAKES UP THE WORLD 


When is a 
diamond not 
a diamond? 


burning all away, it is necessary to keep it 
bottled up in oil 

There is another element which behaves in 
the same strange way calcium does, and we eat 
it every day! Its name is sodium. It is in the 
soda and baking powder with which cakes, 
cookies and biscuits are made light; and com¬ 
mon table salt is nearly half sodium! But we 
would not care to eat it in its pure form. 

That question is really a riddle. To answer 
it we must know what a diamond is. It is 
something with which we are quite familiar— 
carbon. But a diamond is pure carbon . 

But here is the trick which makes the riddle. 
Pure carbon is not always diamond. There is 
a substance called graphite, of which the “lead” 
in your pencil is made. (A “lead” pencil con¬ 
tains no lead!) Graphite is also pure carbon. 
If we hold any cold object in the yellow part of 
a candle flame, we will soon find it covered with 
black soot. This, too, is pure carbon. 

Now the strange thing is that each of these, 
diamond, graphite, and soot (or lampblack) is 


EARTH 


67 


pure carbon. Pure carbon masquerades in these 
three forms. So we might say that a diamond 



The soot which a candle flame deposits on 
any cold object is pure carbon 

is not a diamond when it is the lead in a pencil, 
or a flake of soot on some one’s nose. 

Is an element ever destroyed? No. It may 
combine, and so change its appearance, its 
habits, its name, and the amount of space it 
occupies. But there is one thing that it never 
changes—its weight. 

It never actually gains or loses weight. There 
may be an apparent change of weight, but that 
can always be accounted for by the addition or 
disappearance of something else. 

Iron, in rusting, seems to gain weight. But 


What happens 
to elements? 


68 


WHAT MAKES UP THE WORLD 


the weight it gains is that of the oxygen which 
it takes from the air. 

The candle, in burning, may seem to lose 
weight, but if the carbon dioxide and water 
vapor which it produces were captured and 
weighed, it would be plain that part of the 
candle has changed form, but that nothing 
has actually been lost. 

Elements may change their forms in an 
infinite number of combinations, and these 
combinations are ceaselessly going on all around 
us. But never, so far as all the scientists have 
ever found out, does that which was a some¬ 
thing ever become a nothing. 


Chapter VI 


CHANGES 

I F WE asked a chemist how elements got to¬ 
gether, he would probably answer with a set 
of books so large and long that it would take 
years to read them, and so difficult that it would 
take years more to understand them. That is 
how big the question is. 

The first thing to know about how elements 
get together to form other things, is that when 
two elements are brought together, one of two 
things happens. Sometimes, as when the 
oxygen and hydrogen gases were mixed in the 
jar, the atoms of both kinds just wander about 
among each other like people in a crowd, 
none of whom are going anywhere, and no one 
of whom is walking with anyone else. 

But at other times, the atoms seek each other 
out and join hands in certain combinations. In 


How do elements 
get together? 


69 


7 ° 


WHAT MAKES UP THE WORLD 


carbon dioxide, each carbon atom took two 
oxygen atoms, and they joined together in a 



In a mixture, the atoms wander about separately, 
paying no attention to each other 


sort of ring-around-the-rosy combination which 
was the molecule of the new material known 
as carbon dioxide. 

In the first case, when the atoms do not “join 
hands,” we say that the two elements are mixed, 
or that a mixture has been made. In the second 
case, when the atoms of two or more different 
substances have joined hands to form a molecule 


CHANGES 


7 1 


of a new substance, we say that they have 
entered into combination, or that they have 
united to form a compound. 

In a mixture, the substances which have 
mixed do not lose their original characteristics. 



In a compound, the atoms group themselves into 
molecules which are all exactly alike 


For example—free oxygen in its pure state 
supports combustion. 

In air, which is a mixture, the oxygen, mixed 
though it is with four times its own quantity 
of nitrogen, still supports combustion. The 


What is a 
mixture? 


7* 


WHAT MAKES UP THE WORLD 


What is a 
compound? 


speed of the combustion has been slowed down 
by the quantity of nitrogen which gets in the 
oxygen’s way, more or less, but oxygen has still 
its characteristic eagerness to combine with 
certain other things. 

In water, which is a compound, although 
there is eight times as much oxygen as hydrogen 
by weight, the oxygen shows no signs of its 
usual desire to enter into a combustion process. 
In short, the oxygen in water is no longer 
oxygen, to judge by its behavior, but merely a 
part of water. 

This is always true of mixtures: each sub¬ 
stance keeps its own identity or personality 
although it may be modified by other substances 
in the mixture. But in a compound, each sub¬ 
stance ceases to be itself and becomes merely a 
part of the compound. 

A compound, then, may be something quite 
different from the materials it was made of. 
Water, for instance, is a liquid which neither 
burns nor supports combustion. Yet we know 
that it is made of two gases: hydrogen, which 


CHANGES 


73 


burns; and oxygen, which supports combustion. 
But it is not at all like either of them. 

Furthermore, a compound is made up of 
molecules, each of which contains a certain 
number of atoms of each material which en¬ 
tered into the compound. The number of each 
kind of atoms in a molecule of any certain 
compound never varies. 

Carbon dioxide, for instance, has a molecule 
made up of one carbon atom and two oxygen 
atoms. Nothing in the world that anyone could 
do could persuade a single molecule of carbon 
dioxide to take in another atom of anything, 
and remain carbon dioxide. It might turn into 
something else, but as long as it is carbon 
dioxide its molecules will be made of one atom 
of carbon and two of oxygen. 

It is as if the elements were the letters of the 
alphabet, and compounds were words. Any 
given word must always be spelled the same 
way. The word go, for instance, must always 
have one g and one o. If it has two o's, it is goo, 
which does not mean the same thing as go. 


74 


WHAT MAKES UP THE WORLD 


What causes 
things to 
combine? 


Neither does got, nor ago, nor goat. Go to be 
go, must be spelled g-o. 

In the same way, water, to be water, must be 
made of two atoms of hydrogen and one of 
oxygen. If it were made of two atoms of each, it 
would not be water, but peroxide of hydrogen, 
which is something quite different. The deadly 
gas carbon monoxide is always made of one 
atom of carbon and one of oxygen. It can be 
persuaded to pick up another atom of oxygen 
for each of its molecules, but then it is no longer 
carbon monoxide, but carbon dioxide instead. 

There are endless numbers of compounds, 
just as there is an almost endless number of 
words. But each separate compound has always 
the same materials in the same proportions. 

Some things don’t seem to require any par¬ 
ticular condition to form combinations or com¬ 
pounds. Iron and oxygen, for example, have to 
be kept apart by a layer of paint, or they will 
begin combining without any cause or excuse 
except their own desire to do so. Those excit¬ 
able substances, phosphorus, calcium, sodium, 


CHANGES 


75 


and potassium, combine much more readily 
with oxygen than iron does. They even burst 
into flames without anyone’s having gone to the 
trouble to set fire to them. 

But fortunately, not everything combines as 
readily as these do, or we should find ourselves 
in a world of flames. 

Hydrogen and oxygen seem to be attracted 
to each other. But we can safely mix hydrogen 
and oxygen gases together, and nothing will 
happen at all unless we supply heat. But even 
a very small spark will ignite the whole of the 
mixed gases, which will combine at once into 
water, scattered in minute form through the air 
by the force of the explosion with which the 
combination takes place. 

The carbon of a candle does not begin to 
unite with oxygen until the candle is lit—that 
is, until heat is supplied. Heat is one of the 
most important things in bringing about com¬ 
binations. Many substances which show no 
desire to combine at ordinary temperatures 
combine readily when they are heated. 


7 6 


WHAT MAKES UP THE WORLD 


Oxygen and nitrogen, we know, do not com¬ 
bine readily, or we should soon have no air to 
breathe. But they can be coaxed into combin¬ 
ing by a very great heat. The compound thus 
formed contains one atom of nitrogen to one 
atom of oxygen. This compound when cool 
can be changed to another which has one atom 
of nitrogen to two atoms of oxygen. When 
this is combined with water, the resulting com¬ 
pound has a molecule which consists of one 
atom of hydrogen, one atom of nitrogen, and 
three atoms of oxygen. 

This stuff is a liquid called nitric acid. Al¬ 
though it is made from the same elements as 
air and water, it is a very different thing. It is 
so powerful and destructive that it will eat up 
metal. Cloth touched by it disappears as if 
suddenly burnt up; and when it is spilled on 
skin, the skin immediately becomes brown and 
dead, and a while later peels off. 

Fortunately, it is very difficult to make nitro¬ 
gen combine with oxygen and hydrogen to 
form this terrible acid, for what kind of a world 


CHANGES 


77 


would it be if it rained nitric acid? Not a com¬ 
fortable one to live in! 

There are other things which help elements 
to combine. Electricity is one. Some things 
will combine only if another substance is pres¬ 
ent, but this other substance does not join in the 
combination. This process is not very well 
understood, even by chemists. 

Substances can separate into the original 
elements that composed them. If they couldn’t, 
this old world would some day reach a point 
where all of all its eighty or ninety elements 
had settled down in compounds, and nothing 
more could happen. 

As we already know, compounds can be taken 
apart. Green plants take apart carbon dioxide 
to get the carbon for their food. The scientist 
with the electric current can take apart water. 
If it were not possible to take iron out of its 
combinations with other things in iron ore, we 
would not be living in an “age of steel.” 

There are compounds in which the elements 
seem so little pleased with each other that only 


Do things come 
uncombined? 


7» 


WHAT MAKES UP THE WORLD 


the slightest excuse is enough to jar them apart, 
like people looking for a quarrel. Such combi¬ 
nations are called unstable compounds, while 
steady combinations, such as water, which 
can be taken apart only with great difficulty, 
are called stable compounds . 

Water, or oxide of hydrogen, can be per¬ 
suaded to take on an extra atom of oxygen, 
becoming peroxide of hydrogen. We are well 
acquainted with this liquid as an antiseptic 
which “fizzes” when it is put on an open 
wound, or applied to organic matter. 

Peroxide of hydrogen is an unstable com¬ 
pound. That extra atom of oxygen in each 
molecule seems to feel that “three’s company 
and four’s a crowd.” The extra oxygen atom is 
on the continual lookout for a more congenial 
situation to be in. 

If we leave the peroxide of hydrogen bottle 
uncorked, the stuff will lose its strength. In 
other words, the oxygen atoms will escape, one 
from each molecule, and what is left in the 
bottle will be just water. 


CHANGES 


79 


But if we put peroxide of hydrogen on an 
open wound, these extra oxygen atoms get very 
busy. Oxygen is one of the best purifiers 
known. The little bubbles that immediately 
begin to form are evidence of the way in which 
the oxygen goes to work at once at disinfecting. 

Almost anything will come out of a combina¬ 
tion if it meets something else which has a 
stronger attraction for it than the partner it 
already has. For instance, hydrogen is com¬ 
bined with carbon in the candle wax. But as 
soon as the opportunity comes for that hydrogen 
to join oxygen—that is when heat is supplied 
—the hydrogen immediately deserts. The 
hydrogen-carbon combination is thereby broken 
up and rearranged. 

There are few things that have a greater 
attraction for oxygen than hydrogen has, but 
among these few are calcium and sodium. The 
oxygen deserts the hydrogen to join the calcium 
and sodium—and even the stable compound 
hydrogen oxide is broken up, or, as the chemist 
would say, decomposed . 


8o 


WHAT MAKES UP THE WORLD 


Whenever a compound is broken up into 
simpler compounds, or into its original ele¬ 
ments, it is decomposed. Water is decomposed 
by an electric current, and hydrogen and 
oxygen are produced. 

Much that is now known about the earth 
and what it is made of has resulted from man’s 
learning to take things apart. 


Chapter VII 


THE STORY OF CHEMISTRY 

T O WONDER what things are made of, 
and how, and what they are good for, is 
one of the most natural things in human nature. 

Even a baby shows this trait. A baby is not 
much of a scientist, because his equipment is so 
limited. But he has eyes to see, fingers to feel, 
and a mouth to taste. When he finds a strange 
object he grasps it. If he can, he picks it up. He 
turns it over several times with his curious 
fingers, looking at it closely. Then he subjects 
it to what is, for him, the final test—he puts it 
in his mouth to see if it is good to eat. If it is 
not, he may later try to pull it apart to find out 
how it is made. 

The earliest scientists had little more to work 
with than the baby has. Lacking the equip¬ 
ment, they framed elaborate theories about what 


How were things 
found out? 


81 


82 


WHAT MAKES UP THE WORLD 


things are made of. One of the most reasonable 
of these was the theory that the world is made 
of earth, air, water, and fire. 

But even at that time, some men had learned 
that certain things could be separated out of 
“earth.” Copper and gold (which are some¬ 
times found in their pure form in rocks) were 
taken out of the rocks and made into useful and 
beautiful articles. Iron, which is the most useful 
metal of all, was not known then, for it is 
usually found combined with oxygen and mixed 
with impurities in the form of a rusty dirt. 
Men, in those days, did not suspect that this 
reddish dirt contained a metal more useful than 
copper or gold. 

But gold they considered very beautiful. 
Because of its beauty and because it does not 
rust or tarnish, it became very valuable. Certain 
men began to think that perhaps gold could be 
manufactured. Of course, anyone learning to 
make gold would at once become very rich and 
powerful, and would be in a position, if he 
wished, to rule the world. 


THE STORY OF CHEMISTRY 


83 


A number of men, then, began to try to do 
this tremendous thing;. These men were called 
alchemists. 

No one knows exactly how long ago it was 
that men began to try to make gold. But it is 
certain that the first alchemists had very little 
knowledge with which to go about the task. 

There were no microscopes or implements of 
that kind. Electricity was quite undreamed 
of. They had no equipment with which to 
procure pure elements with which to work. 
Indeed, they knew of no elements but earth, 
air, water, and fire, which we now know are not 
elements at all. 

The first alchemists had little beside fire to 
help them. It was probably not long before 
they learned to distill —that is, to heat a sub¬ 
stance and catch the steam or vapor which 
comes off it, and then, by cooling, to condense 
this vapor into a liquid. 

Gradually they learned a number of other 
tricks for taking things apart or putting them 
together. In the course of hundreds of years, 


Why did the 
alchemists 
give up? 


8 4 


WHAT MAKES UP THE WORLD 


What is 
an atom? 


the alchemists began to discover that there were 
many different and distinct materials in the 
earth, which we know now as elements. 

In trying to combine various things to make 
gold, they produced mixtures and compounds 
which disclosed more elements. 

We know now what the alchemists did not 
know—that gold is one of these elements, and 
that an element cannot be made of anything but 
itself. The alchemists were working at a hope¬ 
less task. But, while it was impossible for them 
to realize their goal, they did something else 
quite as valuable to the world. They laid the 
foundations of a great science, known to the 
world as chemistry. 

Alchemy became chemistry gradually, as the 
hope that gold could be manufactured became 
more and more improbable in the light of the 
truths which had been learned in the long 
and futile search. 

Strangely enough, the idea of the atom origi¬ 
nated back in the time when the elements were 
thought to be earth, air, water, and fire. 



Little by little, the alchemists laid the foundations 
. for the science of chemistry 


85 


« 

































































































































































































































86 


WHAT MAKES UP THE WORLD 


The ancient Greeks wondered whether mat¬ 
ter could be divided indefinitely. That is, if 
you took a quantity of some pure substance, and 
then took half of it, and half of that, and half 
of that and so on, would you ever arrive at 
anything that couldn’t be divided? 

Some of them thought that such a thing 
would be arrived at, and called that thing an 
atom, which, in their language, meant a thing 
which could not be cut. 

Only a little over a hundred years ago, the 
same theory was brought out, argued over a 
great deal, and finally accepted as true. 

No one has ever yet seen an atom. It is the 
way substances behave which has persuaded 
scientists that atoms really exist. It is much too 
difficult a subject to be explained here. But 
although no one has yet seen an atom, the 
camera, which has a much more perfect eye 
than anything living, has caught pictures of 
atoms. In these pictures, atoms make little 
streaks, for an atom will not stand still to have 
its picture taken. 


THE STORY OF CHEMISTRY 


87 


The reason that there is only a certain 
number of elements in the world, is that there 
are only that many kinds of atoms. Com¬ 
pounds, you remember, are made of groups of 
atoms, which are called molecules. Molecules 
are also too small to be seen, even with the most 
powerful microscopes. 

Radium is one of the more recently discovered 
of the elements. From the very first, it was 
evident that this new element had some tricks 
all its own. 

It was named radium because, before it was 
even found, its rays or radiations were noticed. 
As radium was studied, it was found that it 
produced three different kinds of rays. 

One of them resembles light, except that it 
is invisible, and can pass right through most 
things. A photographic plate, which is much 
more sensitive in some ways than the corre¬ 
sponding part of the human eye, is able to pick 
up these rays as if they were light. 

Another of the three kinds of radium rays 
is a sort of electricity. 


What is the 
mystery of 
radium? 


88 


WHAT MAKES UP THE WORLD 


But the greatest wonder of all is the other ray 
of radium. It has been found that this ray is 
made up of a stream of helium atoms traveling 
at an enormous rate of speed! 

Now radium is considered an element, and 
so is helium. Contrary to all rules and regu¬ 
lations for elements, radium seems to be making 
another element—helium—out of itself! 

Radium, in giving off its three kinds of 
rays, gradually decays. Scientists, studying the 
rate at which radium wastes itself away, have 
figured out that even if, at one time, the whole 
world had been made of radium there would 
be none of it left by now! 

But radium does exist in the world now, 
although in very small quantities. There has 
probably never been a much greater quantity of 
it than there is now. Therefore, something 
must be making radium about as fast as radium 
is decaying. This thing which produces radium 
is believed to be the element known as uranium . 

The more scientists learn, the more they find 
there is to learn. The mystery about radium is 


THE STORY OF CHEMISTRY 


89 


one of the many interesting things that have 
still to be learned about. 

Someone will some day find out an explana¬ 
tion for the radium mystery. As yet we can 
only guess about it. 

This much can be said in explanation. An 
atom is not a tiny particle of solid matter, like 
a small grain of sand. It is believed to be made 
up of tiny charges of electricity. Some atoms 
are very complex, while others are quite simple. 

Uranium and radium have very complex 
atoms. In the natural decay of radium, elec¬ 
trical particles and helium particles are shot 
out of the radium atoms as they break down, 
just as rocks, smoke and ashes are thrown out 
of an erupting volcano. Naturally, the radium 
atom, in giving out the helium and electricity, 
is itself changed to something else. 

The disintegration of radium may be thought 
of as a process of simplifying the complex atoms 
of radium into simpler atoms representing 
other elements. 

Now it is quite possible that one element can 


Can the 
alchemists’ 
dream come 
true? 


9 o 


WHAT MAKES UP THE WORLD 


be transformed into another element having a 
simpler atom. This has actually been accom¬ 
plished in quite a number of cases, but only on 
a very minute scale. 

It is possible, therefore, that someone may 
someday change some other material into gold. 
Perhaps the gold so created would be more 
costly than natural gold. But still, the alchem¬ 
ists dream may yet come true. 

The great science of chemistry is full of such 
exciting possibilities as this. Columbus, setting 
sail across an unknown sea, with a whole world 
waiting ahead of him to be discovered, had no 
greater possibilities before him than the chem¬ 
ists of today and tomorrow. 


Chapter VIII 


EVERYDAY CHEMISTRY 

T HERE are many people who think that 
scientists, such as chemists, have no real 
part in the life of the world, but live in a sort 
of world of their own, surrounded by their 
queer apparatus and thinking in terms of 
formulae and equations. 

But it is a very great mistake to think that the 
scientists, particularly the chemists, are not 
extremely practical folk. It is easy to realize 
that such striking discoveries as helium and 
radium, with the great advancement they have 
brought to aviation and to medicine, are the 
direct result of the chemists* researches. 

It is not so easy to see, but it is quite as true, 
that almost everything which happens to us in 
our daily lives, almost everything we use, is in 
some way helped, regulated or improved by the 


What does 
chemistry do 
for the world? 


91 


92 


WHAT MAKES UP THE WORLD 


knowledge which chemists and other scientists 
have given the world. 

The houses that we live in are built of wood, 
stone, mortar, concrete, plaster, metal and glass. 
Of these, only wood and stone are simple 
products of nature. The rest are made by man 
by processes which are basically chemical. 

The food we eat comes from the soil, through 
the medium of plants, or of animals which eat 
plants. Famine or plenty, poverty or prosperity 
depends largely upon whether the soil produces 
poorly or generously. The chemist, studying 
the soil, can tell the farmer how to make even 
poor soil grow good crops. 

In the past, mankind has worn clothes made 
mostly of cotton and flax, which are plant 
fibres, wool from sheep, and silk from the 
cocoon of a caterpillar. But man the chemist 
has learned to make a kind of silk out of wood, 
or cornstalks, and the worthless part of cotton. 

Man has learned to take a greasy stuff called 
petroleum out of the earth, and make it into a 
thin clear liquid—gasoline—which he uses to 


EVERYDAY CHEMISTRY 


93 


make his modern chariots speed very many 
times faster than the horse-drawn chariots of 
the ancients. 

He has taken a sticky black stuff out of coal, 
and out of this coal tar he has created not only 
medicines, but fragrant perfumes, delicious 
flavors, and hundreds of beautiful dye tints with 
which cloth is colored. 

The chemist, it seems, has far outstripped the 
fondest dreams of the alchemists, who hoped 
only to make gold. But although the chemist 
has almost seemed to dip into the realm of 
magic, his greatest gifts to mankind are of a 
more practical, everyday aspect. 

The release of the power in gasoline, the 
making of simple but useful materials such as 
mortar, the discovery of scientific principles for 
the raising of crops, and the manufacture of 
everyday commodities such as glass bottles and 
jars—it is by such ways as these that our civili¬ 
zation has been advanced. 

Gasoline is made of the same materials as the 
candle. Of course, there are many kinds of 


94 


WHAT MAKES UP THE WORLD 


How does 
gasoline ma\c 
the engine go? 


gasolines, and they are not exactly alike. A 
molecule of gasoline is a rather complicated 
affair, but it is made up of atoms of carbon and 
of hydrogen. There may be some other kinds 
of atoms in the molecules of different kinds of 
gasoline, but the carbon and hydrogen are the 
important things. 

In an automobile engine, there are a number 
of cylinders . Each cylinder is like a little 
round room. There is a sort of movable plug, 
which is called a piston, filling the open end 
of the cylinder. 

A lever is attached to this piston, so that when 
the piston moves, the lever moves too. The 
motion of the lever is finally transferred to the 
wheels of the car. The wheels turn, and the 
car moves. 

Now this is what happens inside the cylinder. 
Gasoline, mixed with air, is sprayed into the 
cylinder. A spark is shot through it. The 
carbon and hydrogen of the gasoline need only 
this spark to start combining with the oxygen 
of the air. 


EVERYDAY CHEMISTRY 


95 


The combination takes place very quickly. 
The hydrogen and oxygen form water vapor, 
and the carbon and oxygen form carbon dioxide. 
The water vapor and the carbon dioxide gas 
both want a great deal more space than they 
did as gasoline and air, and they want it very 
suddenly. 

So they push the piston out of their way in 
order to take the room they need. The sudden 
thrust which the explosion gives the piston is 
carried to the wheels, and the automobile moves 
forward as the driver desires. 

In the meantime, the cylinder is emptied and 
the piston pushed back up into position, ready 
for another explosion. The cylinders take 
turns so that the repeated thrusts of the pistons 
gives a smooth flow of power. 

Hydrogen is more eager for oxygen than 
carbon is. If there is any shortage of oxygen, 
it is the carbon which gets left out. Further¬ 
more, when a gasoline engine is first started, the 
engine is cold. Now, carbon needs more heat 
in order to start combining with oxygen than 


9 6 


WHAT MAKES UP THE WORLD 


hydrogen needs. While the engine is too cold 
for all the carbon to unite with oxygen, some of 




The gasoline and air combine to form carbon dioxide 
and water vapor which demand much more space 

the carbon may combine with one atom of 
oxygen instead of two. 









































EVERYDAY CHEMISTRY 


97 


Here we have the deadly poison carbon 
monoxide gas, which you can neither see nor 
smell. There is very little danger from it in 
the open air. But if a cold gasoline engine is 
started in a closed garage, carbon monoxide 
may accumulate faster than it can get away. 
Many people have been overcome in closed 
garages, due to ignorance of this poisonous gas. 

Mortar is the stuff that holds the bricks to¬ 
gether in a brick wall. But what is it made of? 
What makes it so hard that, in an old wall, it 
is harder than even the bricks themselves? 

The story starts with limestone. Limestone 
has a molecule made of an atom of calcium, an 
atom of carbon, and three atoms of oxygen. 
Limestone is put in a sort of great oven, called 
a lime kiln, and baked. 

In this baking process, the carbon atom and 
two oxygen atoms fly away together as carbon 
dioxide. What is left has an atom of calcium 
and one of oxygen. It is therefore oxide of 
calcium, but it is always called lime . 

Plain white mortar is made by mixing lime, 


What is mortar? 


9 8 


WHAT MAKES UP THE WORLD 


sand, and water. When this is spread between 
the bricks, two things begin to happen. 

The water begins to dry out, or evaporate. 
But while the water is drying out, something 



When mortar is spread between bricks a 
chemical action begins 

else is coming in. The mortar soaks up carbon 
dioxide from the air. 

When limestone was baked, carbon dioxide 
came out of it, and lime was left. If carbon 
dioxide comes back in and joins the lime, what 







EVERYDAY CHEMISTRY 


99 


do you have but limestone again, this time with 
sand in it? 

That is exactly what mortar is. But to look 
at a piece of limestone, would you have sup¬ 
posed that it could be made to lie between 
bricks, binding them together? The sand 
makes the mortar stronger. The older the 
mortar is, the stronger it becomes, for all of the 
lime is gradually changed back to limestone by 
the carbon dioxide from the air. 

Man, in his long process of learning, has 
frequently learned things by accident, long 
before he learned why they were so. He prob¬ 
ably learned that a fire needs a draft thousands 
of years ago, although nothing was known 
about oxygen until about the same time that the 
American colonists first began to think about 
fighting for their freedom. 

In the same way, farmers discovered that 
certain things, such as manure, seem to have a 
good effect upon crops. It is probable that they 
also found by experience that things grew better 
if the same crops were not always planted in 


How does 
chemistry help 
the plants grow? 


100 


WHAT MAKES UP THE WORLD 


the same fields. But just why these things are 
so, no one, then, knew. 

For, of course, no one knew about nitrates, 
those compounds of nitrogen which plants must 
take out of the soil in order to live. Animals 
have to get these same nitrates from the plants. 
But animals don’t use all of the nitrates which 
they eat. Therefore, when a farmer spreads 
manure from his barn upon a field, he gives 
back to the field some of the very same nitrates 
which the plants have taken out of it and which 
the farmer’s animals have eaten but not used. 

Since nitrogen does not combine very easily 
with other things, there are not many places in 
the world where nitrogen compounds are found 
in abundance. In South America, in the Re¬ 
public of Chile, there is a large quantity of a 
nitrate called Chile saltpeter. It is made of 
nitrogen, sodium, and oxygen. 

Before the war, all the great countries of the 
world bought saltpeter of Chile, to put on their 
fields to make their crops grow. But unfortu¬ 
nately, saltpeter is also used in making gun- 


EVERYDAY CHEMISTRY 


IOI 

powder and explosives. During the war, no 
country could get enough of it. In the United 
States, men began to make nitrogen compounds 
by taking nitrogen out of the air to give to the 
crops to make them grow. 

When farmers first found that by changing 
the crops in their fields from year to year, they 
got more produce, they probably did not know 
why it was so. 

Just as green plants, and nothing else, can 
take carbon out of carbon dioxide, so a certain 
kind of bacteria can do what no other plant or 
animal can—take nitrogen out of the air and 
put it in the soil in the form of compounds 
which plants can use. 

These bacteria, which are so tiny that only 
with a powerful microscope can they be seen 
at all, live in little nodules or bumps on the roots 
of certain plants. The clover plant is one of 
the most important of these. 

If a farmer grows clover in a field one year, 
there will be enough nitrogen left over in the 
soil so that he can grow a good crop of some- 


102 


WHAT MAKES UP THE WORLD 


What is glass? 


thing else there the next year. This is called 
rotation of crops, for rotation means nothing 
more than taking turns. 

Glass was probably first discovered by acci¬ 
dent, and it is very likely that this accident 
happened in Egypt. 

Egypt has a very sandy soil, and sand is 
dioxide of silicon. Glass is mostly silicon. It 
seems quite possible that all of the materials 
necessary to make a small piece of glass might be 
present in a burning straw stack on the sandy 
soil of Egypt. Even the heat necessary to fuse, 
or melt together, the materials would be 
supplied by the fire. 

It may be that some ancient Egyptian, stirring 
around in the ashes where his straw stack had 
burned, found something that the world had 
never seen before—a little blob of glass. 

But accidental as the first glass making may 
have been, today it is very scientific. 

Glass is a mixture of compounds. It can be 
made of various materials, but silicon and oxy¬ 
gen, usually in the form of sand, are the most 



Glass was probably first discovered by accident 
in ancient Egypt 


103 















104 


WHAT MAKES UP THE WORLD 


important and are always necessary. Glass 
usually contains some calcium in the form of 
lime, and some sodium or potassium. Sodium 
is used in soft glass, and potassium is used in 
hard glass. Although all glass may seem hard 
to you, it would not seem so if you were a glass 
cutter by trade. 

Many other materials may be put in glass to 
change its quality or its color. Iron is an im¬ 
purity in glass which makes it look greenish. 
Since it is difficult to get all the iron out, cheap 
bottles are often green. 

The purpose for which the glass is to be used 
determines what it shall be made of. If it is 
to be used for spectacles, it is very important 
that it shall be perfectly clear and flawless. If 
it is for milk bottles, it needs to be white, so 
that the milk won’t look queer in it, and it needs 
to be tough, so that the bottles won’t break 
very easily. 

All the materials, together with some broken 
glass, are melted up together in an enormous 
sort of kettle. The dirt and impurities can be 


EVERYDAY CHEMISTRY 


105 


skimmed off the top. Then it is ready to be 
made into window panes or bottles or spectacle 
lenses or whatever it was meant for. 

To make plate glass, the thick, heavy liquid 
glass is poured out on a great flat table and 
rolled with big rollers. Bottles are made by 
blowing the glass as if it were a soap bubble, 
but with a mould around it to shape it. There 
is no danger of this kind of a bubble bursting 
if it touches something, for it is very tough. 

Imagine, if you can, a time when windows 
were made of oiled paper or skins instead of 
glass. A little light came in, but of course you 
couldn’t see out. Instead of bottles there were 
earthenware jugs and leather bags. Instead of 
drinking glasses people used mugs and metal 
cups, or dippers made from gourds. 

When Columbus crossed the Atlantic he 
found the natives of Santo Domingo playing 
with balls made from the gum of a tree. An¬ 
other explorer found that in South America 
certain Indians smeared this gum over their 
coats to keep dry in the rain. 


What is 
rubber? 


106 WHAT MAKES UP THE WORLD 

When a lump of this stuff was sent to the 
man who had discovered oxygen, he cut it up 
and gave the pieces to his friends to use in 
rubbing out pencil marks when they made 
mistakes. They asked him what the queer bits 
of gum were, and he replied that they were 
“India rubbers.” 

To this day we call the gum of the caout¬ 
chouc tree “rubber,” whether we are using it 
to rub out our mistakes or to keep our feet dry 
or to tire our automobile wheels. 

But it was many years after rubber was used 
to erase with before it was used for other pur¬ 
poses. The stuff was sticky in hot weather, 
and smelled very unpleasant. 

About a hundred years ago, scientists learned 
that if rubber is mixed with some sulphur and 
treated with heat it becomes quite a different 
thing. It becomes the tough, stable, elastic 
solid which we are familiar with in the form 
of hot water bottles, rubber heels, and balls. 

This process is commonly known as “vul¬ 
canizing ” If a greater quantity of sulphur is 


EVERYDAY CHEMISTRY 


107 


used, the product is a hard, almost brittle sub¬ 
stance. This hard rubber is used for combs, 
pen holders, knobs, handles, and many sorts of 
useful articles. 

Vulcanized rubber has become so tremen¬ 
dously useful that not enough caoutchouc trees 
grow in the world to supply all the rubber that 
men would like. Consequently, scientists have 
been searching for years to find a new source 
from which rubber might be made. 

In order to make rubber, it is necessary to 
know what rubber is composed of. Pure rub¬ 
ber has a molecule made of ten atoms of carbon 
and sixteen atoms of hydrogen. It can be de¬ 
composed by heat into a compound called 
isoprene, which has a molecule of five atoms 
of carbon and eight of hydrogen. 

It is easy enough to make the rubber mole¬ 
cules split in two to form isoprene molecules. 
But it took the chemists many years to persuade 
isoprene molecules to join together in pairs to 
make rubber molecules. 

Isoprene is a clear liquid. It can be made 


108 WHAT MAKES UP THE WORLD 

out of turpentine, which is made from the sap 
of a kind of pine tree. It can be made from 
starch, which in turn can be made from po¬ 
tatoes, and corn, and many other things. 

Isoprene can be made out of saw dust, and 
it can even be made out of coal and lime. The 
scientists who have been working for many 
years on this fascinating problem have dis¬ 
covered many ways of making isoprene, for 
isoprene is made of only carbon and hydrogen, 
and these are very common elements. 

But the rubber that is being used for tires 
and overshoes and the thousand and one every¬ 
day purposes of this useful stuff, is still made 
from caoutchouc tree gum. And the reason 
for this is that rubber made out of potatoes, or 
turpentine, or sawdust, or any of these other 
substances, is too expensive. 

But the hunt for cheaper rubber goes on. 
Someday a way will be found for making rub¬ 
ber which will cost less than caoutchouc gum 
rubber, and then rubber will be used for many 
more things than it is now. It will be a quieter 


EVERYDAY CHEMISTRY 


109 

world when houses are built of rubber and 
streets are paved with it, for rubber deadens 
sound, as a pair of rubber heels will show. 

The work of the chemist, in general, is 
divided into two great parts: analysis, which 
means taking things apart; and synthesis, 
which means building things up out of other 
and simpler things. 

Thus, the chemist analyzed rubber and 
found it was made of carbon and hydrogen in 
a certain compound. But when the chemist 
made rubber out of potatoes, he synthesized 
rubber, or made synthetic rubber. 

It is much easier to take things apart than 
it is to put them together, just as it is easier to 
break things than to make them. Only in the 
last fifty or a hundred years has the science 
of chemistry advanced to the point of synthetic 
or creative chemistry. 

Always in the past, if man wanted a material, 
he had to look about him and find it. Perhaps 
what he found didn’t fit his purpose very well, 
but it was the best he had, and he had to use 


What is a 
synthetic? 


no 


WHAT MAKES UP THE WORLD 


What is 
rayon? 


it. Creative chemistry makes it possible for 
him to create something which exactly fits 
his requirements. 

For instance, for thousands of years man 
has depended upon a caterpiller to spin the 
fibre to make his finest fabrics. The silk 
worm spins a tiny thread of silk for his own 
purpose, not for man’s. The worm makes the 
thread of the thickness and length which just 
suit his own requirements in making himself 
a good cocoon. 

Man, if he wanted silk, had to take what 
the worm made, and make the best of it. But 
what has synthetic chemistry to do with silk? 

The carbon which green plants take out of 
the carbon dioxide from the air is used to 
make a substance called cellulose. Wood is 
mostly cellulose; so is cotton; so is the corn¬ 
stalk. Cellulose is composed of carbon, hydro¬ 
gen, and oxygen. 

Cellulose can be dissolved in certain chem¬ 
icals. In this liquid form, it can be squirted 
out through tiny holes, just as toothpaste 


EVERYDAY CHEMISTRY 


hi 


comes out of the tube. This is the very 
method by which spiders, silk worms, and 
other little creatures spin their silk threads. If 
the toothpaste dried to form a sort of rope, 
you would have exactly the same kind of thing 
on a larger scale. 

The threads made in this way can be just 
as long and just as thick or thin as man, the 
maker, wants to make them. Instead of being 
a few inches long, like the best cotton fibres, 
or many feet long, like silk fibres, the artificial 
silk, or rayon, fibre can be made any length 
that the cloth maker wants it. 

Rayon can be made of cornstalks, or of the 
fuzz that sticks to cotton seeds, or of spruce 
trees. It is not yet as strong as silk, but there 
is every reason to believe that it may someday 
be made so. And it is already much less ex¬ 
pensive and very widely used. 

Once man was entirely dependent for his 
shelter and food and clothing upon things 
which he could find about him, almost ready 
for use. Primitive men lived in caves for 


WHAT MAKES UP THE WORLD 


112 

houses; they ate berries and nuts and roots 
and the flesh of the animals which they could 
kill; they were clothed in the skins of these 
same animals. 

As time went on they learned to use more 
and more of the things about them. They 
hewed logs to make warmer, dryer shelters 
than the caves had been. They learned to cul¬ 
tivate crops in order to provide more plentiful 
and nourishing food. They learned to spin 
and weave cloth from the wool of sheep and 
the fibres of the flax and cotton plants. 

Now man is learning to create the materials 
which he needs out of other, less useful things. 
The synthetic products which man will make 
in the future will be as much better suited to 
man’s use as the modern house is better and 
more comfortable than the dark, damp caves 
which man once called home. 













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